@aws-amplify/auth
Version:
Auth category of aws-amplify
50 lines (47 loc) • 1.84 kB
JavaScript
import { Sha256 } from '@aws-crypto/sha256-js';
import { getCrypto, base64Encoder } from '@aws-amplify/core/internals/utils';
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
const CODE_VERIFIER_CHARSET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
/**
*
* @param length Desired length of the code verifier.
*
* **NOTE:** According to the [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636#section-4.1)
* A code verifier must be with a length >= 43 and <= 128.
*
* @returns An object that contains the generated `codeVerifier` and a method
* `toCodeChallenge` to generate the code challenge from the `codeVerifier`
* following the spec of [RFC 7636](https://datatracker.ietf.org/doc/html/rfc7636#section-4.2).
*/
const generateCodeVerifier = (length) => {
const randomBytes = new Uint8Array(length);
getCrypto().getRandomValues(randomBytes);
let value = '';
let codeChallenge;
for (const byte of randomBytes) {
value += CODE_VERIFIER_CHARSET.charAt(byte % CODE_VERIFIER_CHARSET.length);
}
return {
value,
method: 'S256',
toCodeChallenge() {
if (codeChallenge) {
return codeChallenge;
}
codeChallenge = generateCodeChallenge(value);
return codeChallenge;
},
};
};
function generateCodeChallenge(codeVerifier) {
const awsCryptoHash = new Sha256();
awsCryptoHash.update(codeVerifier);
const codeChallenge = removePaddingChar(base64Encoder.convert(awsCryptoHash.digestSync(), { urlSafe: true }));
return codeChallenge;
}
function removePaddingChar(base64Encoded) {
return base64Encoded.replace(/=/g, '');
}
export { generateCodeVerifier };
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